Albert a



(No' Model.)

A. A. SORG. EXTENSION LADDER.

Patented Deo. 6, 1892.

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UNrTED STATES PATENT OEEICE.

ALBERT A. SORG, OF ANN ARBOR, MICHIGAN, ASSIGNOR OF ONE-HALF TO GEORGE M. OLARKEN, OF SAME PLACE.

EXTENSION-LADDER.

SPECIFICATION forming part of Letters Patent No. 487,301, dated December 6, 1892.

Application iiled September 26, 1891. Serial No. 406,880. (No model.)

To all whom, t may concern: some distance below the point ol' attachment Be it known that I, ALBERT A. SORG, a cit-iof said legs to the plate B, the inner ends of zen of the United States, residing at Ann Arsaid arms being pivotally coupled by means bor, in the county of Vashtenaw and State of of the bolt or rivet e, whereby when the legs 5 Michigan, haveinvented certain new and use- A are spread the arms b will extend horizon- 55 ful Improvements iu Extension-Ladders; and tally, firmly bracing said legs in that position, Ido declare the followingto beafull,cle ar,and as shown in Fig. 2, and when said legs are exact description ofthe invention, such as will closed said arms will fold, as shown in Fig. 3. enable others skilled in the art to which it apf designates a gravitating catch that is Vecic pertains to make and use the same, reference centrically pivoted on the holt or rivet e, that 6o being had tothe accompanyingdrawings, and couples the inner ends of the arms b, and to the letters of reference marked thereon, which is adapted to engage under the hook i, which form a part of this specification. projecting from the lower end of the plate B,

This invention relates to new and useful into which the coupled ends of the arms b 15 improvements in extension-ladders; and it drop when extended to their horizontal. posi- 65 consists in a certain construction and artion, as shown in Fig. 2, in which position rangement of parts, as hereinafter fully set said parts are securely locked by the engagefortl1,tl1e essential features of which being ment of said catchf with the hook a'. The pointed out particularly in the claims. tendency of said catch to swing downward zo The object of the invention is to produce a keeps it in engagement with said hook and 7o ladder that is light and compact when closed, prevents said parts becoming unlocked by that when spreadis securely braced, and that any jar or motion of the ladder. is provided with a vertically-sliding section The extendible section of the ladder is comthat may be readily adj usted to any degree posed of the rails O, coupled by the rounds h,

z 5 of elevation to support a scaffold for ceiling and is provided at the upper end with the 75 work or interior iinishing. This object is atstep or platform D, mounted on the brackets tained by the construction illustrated in the t,secured to the rails O, (clearly shown iu Figs. accompanying drawings, in whichl and 2,) said section being adapted to slide Figure l is a front elevation of the ladder vertically between the supporting-legs A and 3o extended. Fig. 2 is a side elevation of the Within the plates B. The outer faces of the 8o same. Fig. 3 is a side elevation of the ladder rails O are provided with a metal plate E, eX- closed. Fig. 4 is an enlarged vertical section tending from the top to the bottom thereof. on dotted line 4 4 of Fig. 3. Fig. 5 is an en- Said plate is provided with a series of notches larged horizontal section on dotted line 5 5 of or apertures 0, that register with correspond- 35 Fig, 3, ing recesses n in the face of the rails C, as 85 Referring to the letters of reference, A desshown in Fig. 4. ignates the supporting-legs of the ladder, m designates a spring-controlled dog or dewhich are joined in pairs by the steps a, as tent that is pivoted between the ears s, formed shown in Fig. 1. at the upper end of the plate B, the free end 4o B designates T-shaped metal plates. These of said detent being adapted to engage in the 9o plates are located one ou each side of the ladnotches or apertures 0 in the plate F. of the der and are coupled to the legs A by means adjustable section and support said section of the bolts c, passing through the horizonat any degree of elevation, as shown in Figs. tally-extending portions d thereof, whereby l and 2.

45 said legs are pivotallyattached to said plates, Located between the ears s and bearing 95 enabling the lower ends of said legs to be against the under edge of the detent m is a readily spread or contracted, as desired. spring o, (see Fig. 4,) the vtension of which To support the legs A when spread, the causes the free end of the detent to bear brace-arms b are employed, the outer ends of against the plate E, so as to be in position 5o which are pivotally attached to the legs A to automatically engage in the succeeding roo notches therein as the adjustable section is raised, and when said detent is thrown outward to a vertical position, as shown by dotted lines in Fig. 4, said spring will retain it in that position, when it is restrained from engagement with the plate E, permitting the adjustable section to be freely lowered. The upper ends of the legs A are chamfered,as shown at u, the angle being such that when said legs are spread to the limit of thearms b their chamfered ends will stand parallel with the vertical edges of the rails Cof the adjustablek section and support said section between their adjacent faces, as Lshewn in Fig. 2, the

lower ends of said rails Cbeing supported by the bent arms z, formed integral with the lower end of the plate B, that embrace `said rails,.as shown in Fig. 5, and throughwhich the rails are adapted to slide as the adjust-- able section is raised and lowered. j

In the operation of this improved device when itis desired to set up the ladder-the lower ends of the legs A are spread apart theI limit of the arms'b, in which position they are locked by the .catch f,=as before described. The adjustable section is then raised to any: desired height, when it will be supportedbyl `the detents m, engaging in the notches in the railsC, and afford means for sustaining a plank or scaffold at any degree of elevation. To `lower the adjustable section, the detents m are thrown outward to the dottedeposition shown in Fig. 4, when said section maybe vthat the supporting-legs may be opened or closed without affecting the position of the adjustable section and that said section may bev raised andlowered regardless of theposition of the legs. It willalso be seen that this' improved device will serveas 'an ordinary step-ladder when desired.

Having thus fully set forth my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In an -extension-ladder, the combination 'of the side plates, the supporting-legs pivotally coupled to said plates, the vertically-adj ustable section mounted between said legs, and the detents for supporting said section when elevated, substantially as specified.

2. In a ladder, the combination of the T- `shaped plate, the supporting-legs pivoted thereto, the dog or detent mounted on said plate, and the adjustable section adapted to slide vertically between said legs and having notches or apertures to receive said detent, substantially as set forth.

'3. YIn a'ladder, the combination of'the'pivotally-coupled supporting-legs, the brace-arms attached at their outer ends to saidlegs and pivotally coupledat their inner ends, and the gravitating catch for locking said arms when in their horizontal. position to brace said' legs, as set forth. j Y

4. Ina ladder, the combination of the T- shapedplates, the legs pivoted thereto, and the detents mounted on said plates, the adjustable section adapted to slide vertically between said plates and having notches or apertures in which Vsaid detents engage, "the brace-arms attached at their outer ends to the legs and pivotally coupled at their inner ends, the hooks or lugs on the lower endsrof said plates, upon which said arms are adapted to rest when entended,and the catch adapted to engage-'said hooks to loeksaid arms, substantially as specified. l

In testimony whereof I afx my signature in presence of two witnesses.

ALBERT A. SORG.

Witnesses:

GEORGE CLARKE@ ARTHUR BROWN. 

